The present invention relates to a liquid crystal display device, and particularly relates to a liquid crystal display device called a partial transmission type.
For example, the liquid crystal display device called the partial transmission type is used as a compact liquid crystal display device for a portable telephone, etc., and a screen image on the display face can be recognized by reflected light of the sun or the light of a built-in backlight in accordance with necessity.
Namely, areas surrounded by gate signal lines extended in the x-direction and arranged in parallel in the y-direction, and drain signal lines extended in the y-direction and arranged in parallel in the x-direction are set to pixel areas on the liquid crystal side face of one of transparent substrates respectively arranged oppositely through a liquid crystal. A thin film transistor operated by the supply of a scanning signal from one gate signal line, and a pixel electrode for supplying a video signal thereto from one drain signal line through this thin film transistor are formed in each of these pixel areas.
In the pixel area, this pixel electrode has a first pixel electrode also formed as a reflection film in one portion of the pixel area, and a second pixel electrode of a light transmission property formed in at least the other portions except for this one portion. An electric field is generated on the liquid crystal side face of the other substrate between this pixel electrode and an opposite electrode constructed by an electrode of the light transmission property commonly formed in each pixel area. The liquid crystal within the pixel area behaves by this electric field.
In this case, the forming portion of the first pixel electrode also used as the reflection film is used as a light reflection area, and the forming portion of the second pixel electrode of the light transmission property is used as a light transmission area.
The structure that an insulating film (protecting film) also covering the thin film transistor, etc. is formed on the face of one substrate forming the first and second pixel electrodes thereon and an opening portion is formed in the above optical transmission area of this insulating film, is also known. This structure is used to improve the light transmittance of light transmitted through this area.
However, when the liquid crystal display device constructed in this way is used as a light transmission mode and black display is performed, it has been confirmed that light leakage is generated at the boundary of the light reflection area and the light transmission area so that contrast of the display is reduced.
The present invention has been made on the basis of such a situation, and an object of the present invention is to provide a liquid crystal display device for avoiding light leakage.
Typical summaries of the invention disclosed in the present application are explained as follows.
Means 1.
For example, a liquid crystal display device in the present invention comprises a light reflection area for forming a pixel electrode also used as a reflection film in one portion of a pixel area on a liquid crystal side face of one of substrates oppositely arranged through a liquid crystal, and a light transmission area for forming the pixel electrode of a light transmission property in another portion except for at least the one portion;
wherein the pixel electrode also used as the reflection film is formed on the upper face except for an opening portion of an insulating film in which the opening portion is formed in a portion corresponding to the light transmission area, and
the opening portion of the insulating film has a taper formed in a fanwise shape from the substrate side to the liquid crystal side on the side wall face of this opening portion, and at least one portion of this taper is not covered with the pixel electrode also used as the reflection film, but is exposed, and the insulating film has a light absorption property in at least the taper portion.
Means 2.
For example, the liquid crystal display device in the present invention is characterized in that the entire insulating film has the light absorption property with the construction of the means 1 as a premise.
Means 3.
For example, the liquid crystal display device in the present invention is characterized in that the insulating film has a dark color in its light absorption property with the construction of the means 1 or 2 as a premise.
Means 4.
For example, the liquid crystal display device in the present invention is characterized in that the insulating film has a black color in its light absorption property with the construction of one of the means 1 to 3 as a premise.
Means 5.
For example, the liquid crystal display device in the present invention is characterized in that the entire insulating film has the light absorption property, and the light transmittance of its maximum film thickness portion is 30% or less with the construction of the means 1 as a premise.
Means 6.
For example, the liquid crystal display device in the present invention is characterized in that the entire insulating film has the light absorption property, and the light transmittance of its maximum film thickness portion is 10% or less with the construction of the means 1 as a premise.
Means 7.
For example, the present invention also resides in a liquid crystal display device in which each of areas surrounded by gate signal lines arranged in parallel on a liquid crystal side face of one of substrates oppositely arranged through a liquid crystal, and drain signal lines crossing these gate signal lines and arranged in parallel is set to a pixel area;
a switching element operated by a scanning signal from the gate signal line and a pixel electrode for supplying a video signal thereto from the drain signal line through this switching element are arranged in these pixel areas;
the liquid crystal display device has at least an insulating film covering the drain signal line and formed in at least one portion of the pixel area, and
a material also used as a reflection film formed on the upper face of the insulating film in at least one portion of the pixel area as the pixel electrode, and
the insulating film has a light absorption property, and the pixel electrode also used as the reflection film is formed by arranging a clearance between the pixel electrode and the drain signal line when the pixel electrode is seen in a plane.
Means 8.
For example, the liquid crystal display device in the present invention is characterized in that the liquid crystal display device uses a normally black mode in which black display is performed when an electric field applied to the liquid crystal is small with the construction of one of the means 1 to 7 as a premise.
Means 9.
For example, the liquid crystal display device in the present invention is characterized in that a backlight is arranged on the side opposed to the liquid crystal of the one substrate with the construction of one of the means 1 to 8 as a premise.
The present invention is not limited to the above constructions, but can be variously modified in the scope not departing from the technical idea of the present invention.